WikiLeaks, the website that published a quarter-million sensitive diplomatic cables on Sunday, is using Amazon.com Inc. servers in the U.S. to help deliver its information. It sounds like an odd choice, but there are a few reasons it could make sense.

The site cablegate.wikileaks.org, which WikiLeaks is using for the diplomatic documents, is linked to servers run by Amazon Web Services in Seattle, as well as to French company Octopuce. Wikileaks.org, the site’s front page, links back to Amazon servers in the U.S. and in Ireland. Several Internet watchers, including technologist Alex Norcliffe, reported earlier on WikiLeaks’ use of Amazon services.

Amazon and WikiLeaks did not return requests for comment.

The choice of Amazon, a U.S. company, seems strange given the amount of criticism WikiLeaks has received from the U.S. government. Rep. Peter King of New York, the ranking Republican on the House Committee on Homeland Security, sent a letter to Attorney General Eric Holder Sunday saying he supported charging WikiLeaks activist Julian Assange under the Espionage Act.

But experts said it was unlikely that Amazon would face legal action for selling services to WikiLeaks. For one thing, the information might not be considered contraband, particularly now that it is already public, said Jonathan Zittrain, a professor of law and computer science at Harvard University.

“If that data happens in the moment to be in the U.S., that’s really good because we have a First Amendment,” said Eben Moglen, a law professor at Columbia Law School.

Mr. Moglen added that, although where hardware is located can make a difference legally for all parties involved, there wouldn’t be much point in getting Amazon to stop providing services to WikiLeaks. “For all practical purposes … if the law is unfavorable, that Web server process will go somewhere else,” he said.

Using Amazon’s service also makes sense in one important respect: It provides stability when WikiLeaks is attacked, as it was hours before it published the diplomatic communications.

WikiLeaks was hit with a “mass distributed denial of service attack,” the organization said on its official Twitter account Sunday. In this sort of attack, many computers generally flood a server with requests or use other techniques to prevent the server from displaying a Web page.

Arbor Networks, a security-engineering firm, reported that after the attack started, WikiLeaks redirected traffic to its “Cablegate” site from a Swedish hosting provider to the “mirror” sites in France and the U.S., which provide exact copies.

A self-described “hacktivist” known as “th3j35t3r” — or the Jester — claimed responsibility for the attack and wrote on Twitter that WikiLeaks was “threatening the lives of our troops and ‘other assets,’” Andy Greenberg at Forbes reported. Later, the Jester tweeted that the attack was not made from many computers but was a “simple” denial of service hit. On the Jester’s blog, the hacker claims to be “obstructing the lines of communication for terrorists, sympathizers, fixers, facilitators, oppressive regimes and other general bad guys.”